Peripheral arterial cannulation is used during many cardiac surgeries, and is often performed via the femoral artery. Such cannulation is very effective in circulatory support scenarios for cardiorespiratory support, e.g., pulmonary bypass, for patients undergoing various surgical procedures. The cannulation supports a retrograde flow from the femoral artery into the heart, but regular (antegrade) flow is often compromised. The lack of regular antegrade flow results in compromised blood flow to the lower limb (e.g., the leg below the site at which the cannula is inserted into the artery). Such compromised blood flow to the lower limb is often acceptable for the relatively short times involved in many procedures, but in some circumstances it is desirable to provide some blood flow to the lower extremity during the procedure.
To provide increased blood flow to the lower extremity, the cannula may be provided with bi-directional fluid flow capability. Various bi-directional perfusion cannulas have been proposed. One approach has been to use a perfusion cannula with a diameter significantly smaller than the blood vessel lumen diameter in order to permit some blood to flow back over the perfusion cannula, but such systems must be carefully designed and positioned in order to assure appropriate blood flow in the retrograde and antegrade direction. Another approach has been to include an additional perfusion cannula, positioned away from the primary perfusion cannula, to provide antegrade blood flow to the lower extremity. This approach requires the extra cannula as well as an extra perfusion line, as well as associated extra hardware and monitoring. Additional surgeon time is required, as well as an additional puncture in the blood vessel and possible additional incisions in the patient.
Some have included a perfusion port at an antegrade side of the cannula through which blood may flow to the lower extremity. Examples include US Patent Publication 2012/0259273 to Moshinsky et al.; European Patent Application EP 0619745 to Fonger DLP; and U.S. Pat. No. 6,626,872 to Navia. However, such ports must be carefully positioned and constructed to provide proper perfusion flow and to permit easy retraction of the cannula from the artery after the procedure is completed. Sometimes the arterial wall can collapse or constrict against the perfusion port, or a perfusion port extension may interfere with deployment and/or withdrawal of the cannula from the patient.
What has been needed is a perfusion cannula that can selectively provide bi-directional perfusion flow without obstruction of the perfusion ports while also providing for easy deployment and withdrawal of the cannula. The present invention meets these needs.